Turkish opposition parties have been working on a wide ranging alliance program for the elections, sources told Duvar.
The program will include promises on various issues, including the justice system and freedoms.
The parties are also planning to include a guide to the return to an enhanced parliamentary system, according to sources.
The opposition competed in the 2018 elections as the Nation Alliance, which included main opposition Republican People's Party (CHP) and the Good (İYİ) Party. Although not officially a part of it, the Peoples' Democratic Party (HDP) also backed this alliance against the government one.
The parties released a two-page protocol at the time ahead of the elections. Sources said that this time the scope should be widened.
Nearly all of the opposition parties have been working on constitutional changes in line with the return to the parliamentary system, sources said.
Turkish voters said "yes" to shifting the country's governance system to an executive presidency with a controversial referendum on constitutional amendments on April 16, 2017.Turkish nationalist party leader finds results of executive presidential system 'dazzling'
The country shifted to the system officially on July 9, 2018, replacing a 95-year-old parliamentary system.
The system granted sweeping powers to President Recep Tayyip Erdoğan and allowed him to be both the ruling Justice and Development (AKP) leader and the president at the same time.
The opposition has been urging a return to the parliamentary system.
Different from the previous elections, two new parties are set to compete in the elections that are scheduled to be held in 2023.
The Future Party and the Democracy and Progress Party (DEVA), both founded by former high-level AKP officials, are now among the opposition ranks.Turkish government weighs lowering 10 percent election threshold